Throughout this disclosure, the term “Scorpion” or “Scorpion System” refers generally to the disclosed Thomas Services Scorpion brand proprietary tubular management system as a whole.
This Background section is directed to identifying technical problems in cleaning and inspecting, tubulars in the oil and gas exploration field, for which embodiments of the disclosed Knuckle-Jointed Lance (“KJL”) are useful in addressing. However, it will be understood that deployments and applications for the disclosed KJL are not limited to cleaning and inspection of tubulars. This Background section (and the other disclosure herein) describes the KJL as used in cleaning and inspection of tubulars by way of an exemplary application only.
In conventional tubular cleaning operations, the cleaning apparatus is typically stationary, while the tubular is drawn longitudinally past the cleaning apparatus. The tubular is rotated at a relatively slow speed (in the range of 50 rpm, typically) while stationary, spring-loaded air motors drive spinning wire brushes and cutter heads on the inside diameter of the tubular as it is drawn past, via skewed drive rolls. These air brushes are colloquially called “cutters” although they perform abrasive cleaning operations on the internal surface of the tubular. Internal tubular cleaning operations typically also include hydroblasting in the prior art, although this is conventionally understood to be supplemental to the wire brush cleaning described above, rather than a primary cleaning process in and of itself. Typically this conventional hydroblasting is a low pressure water or steam pressure wash at pressures ranging from about 2,500 psi to 3,500 psi.
Good examples of conventional tubular cleaning apparatus are marketed by Knight Manufacturing, Inc. (formerly Hub City Iron Works, Inc.) of Lafayette, La. These products can be viewed on Knight's website.
One drawback of conventional tubular cleaning apparatus is that, with the cleaning apparatus stationary and the tubular drawn longitudinally across, the apparatus requires a large building. Range 3 drilling pipe is typically 40-47 feet long per joint, which means that in order to clean range 3 pipe, the building needs to be at least approximately 120 feet long.
In order to reduce footprint, the tubular may be held stationary and rotated, while cleaning and inspection tools (on the distal end of hoses, wires, etc.) may be inserted or “stabbed” into the interior of the stationary, rotating tubular. Advantageously the hoses, wires, etc. (including multiples thereof) may be inserted into the tubular inside a segmented lance. In addition to being a carrier of multiple hoses, wires, etc. a segmented lance may provide sufficient rigidity to deliver tools to a far end of a long rotating tubular in response to a “push force” inserting the lance at a near end. At the same time, a segmented lance may also provide flexure in at least one direction to enable the lance to be rolled up and unrolled onto and off a reel when extending and retracting the lance. Additionally, by absorbing such contact wear itself, a segmented lance protects the hoses, wires, etc. carried inside the lance from contact wear against the interior of the rotating tabular during operations.
U.S. Pat. No. 6,543,392 to Ashton et al. (“Ashton”) discloses a segmented lance for cleaning and inspecting the interior of individual tubes in tube bundles in steam generators. One of the problems Ashton seeks to solve is to deliver remote cleaning tools and inspection devices initially through a horizontal portion of a steam generator tube, then round a 90-degree deviation in the tube, and then up a vertical portion of the tube. One embodiment disclosed in Ashton provides segmented lance for delivering remote tools and devices,. The segmented lance includes a hinged connection between lance segments, in which rotation about the hinges is limited to incremental deflection between neighboring segments. As a result, the lance retains rigidity in response to a “push force” while still having sufficient flexure (via cumulative relative rotation about consecutive pinned connections) to enable an eventual 90-degree turn.
FIG. 17 of Ashton discloses details of the hinged connection between neighboring lance segments. The Ashton segment design presents several drawbacks. FIG. 17 shows the hinge pins fixed rigidly on one end of the segment. Ashton provides no disclosure as to how the segments are assembled into a lance. FIG. 17 suggests that the ears on one end must be pried apart wide enough so that the ear holes may slide over the fixed pins. This is an inherently weak design, in which the ears must necessarily be made of weak, elastic material to slide over the pins. As a result, the overall segmented lance will also be weak and elastic. If the ears, are made of a harder material, such as metal, then prying them apart to slide over the pins will subject the ears to deformation, cracking or even failure. A much improved design would provide holes at each of the conjoined ends of neighboring segments, with a trunnion or other pin inserted through both sets of holes to faun a pinned connection. This design would permit assembly without stressing the ears, and would strengthen the hinged connection itself by putting the axis of rotation in a location surrounded by segment wall material.
A further weakness in the Ashton hinged connection design is that with the pin in its disclosed position on FIG. 17 near the very tip of a segment. the assembled lance allows sharp bends between neighboring segments. Hoses and cables to be carried inside the lance (see Ashton FIG. 18) may have minimum bend radius specifications for which sharp lance bends such as suggested on Ashton FIG. 17 might be non-compliant. An improved design would provide safeguards against sharp lance bends that might possibly damage internal hoses or cables.
The overall segmented lance disclosed by Ashton also presents several drawbacks. First, Ashton's segmented lance embodiment may not be properly designed to make a 90-degree turn as drawn up in Ashton. FIGS. 17 and 18 of Ashton illustrate lance segments that are permitted limited incremental relative rotation, whose cumulative relative rotation eventually allows a 90-degree turn. FIG. 21 of Ashton illustrates a drive mechanism for the segmented lance that causes the lance to make a sharp 90-degree turn that would be impossible in view of Ashton's FIGS. 17 and 18. Second, a segmented lance such as disclosed in Ashton is likely to encounter additional forces during operations. For example, a “push force” may cause the lance to twist as the lance moves along the tube. As a result, torsional forces will exert themselves on the hinged connections. In addition, inertia and friction forces, plus the dead weight of the lance, will all likely combine to exert compression forces on the hinged connections. In sum, the hinged connections are likely to come under considerable stresses during operations. The hinged connections are also the weakest points of the segmented lance. Ashton's pin enabling the hinged connection (as seen on Ashton's FIG. 17) is located at the very tip of each lance segment, and is thus particularly weak in its native state. Ashton further discloses no safeguards to mitigate against the additional forces and stressed likely to be encountered by Ashton's hinged connection during operations, as described above. It should be noted that failure of a hinged connection during operations as described by Ashton could be highly disadvantageous, potentially leaving, a portion of the lance stranded in a remote section of tube, and retrievable only with great difficulty.
Furthermore, Ashton makes no disclosure how the segmented lance is stored during extension and retraction of the lance during cleaning and inspection operations, much less during periods when not in use. Ashton further does not address measures that may be required to minimize and alleviate bending stresses exerted on hoses or wires carried inside the segmented lance when the lance turns through 90 degrees from horizontal to vertical, especially through the sharp 90-degree bend illustrated on Ashton's FIG. 21.
There is therefore a need in the art to improve the design (and ultimately, the performance) of segmented lances similar to those disclosed in Ashton. Ideally, such improved designs will strengthen the lance, particularly at the hinged or pinned connections, in order to make the lance less susceptible to failure during operations. Such improved designs will also address compact storage of the lance (advantageously on a reel), with the lance in an unstressed state during such storage, both during extension/retraction operations and during periods of non-use